Question

The energy of thermal neutrons is nearly

• A. $0.25$ $eV$
• B. $0.025$ $eV$
• C. $200$ $MeV$
• D. $0.025$ $Joule$

Answer 1

Answer: (B)

$0.025$ $eV$

A thermal neutron is a free neutron with a kinetic energy of about $0.025eV$ (about $4.0\times {10}^{-21}J$ or $2.4MJ/kg$, hence a speed of $2.2km/s$), which is the energy corresponding to the most probable velocity at a temperature of $290K$.